[HomeBrew] Transmitter design concerns/help

[James C. Garland]

>
>
>>  -I have a 600 VCT, 250 mA xfmr I also bought a few years back from 
>> Antique ES. Can I full wave bridge the secondary to produce 600 VDC 
>> while I bring out the center tap to a cap/inductor circuit to provide 
>> 300 VDC for the lower voltage circuits? I suspect that between the amp 
>> and the osc/driver, I shouldn't be "railing" the power supply's 250 mA 
>> capability. Sounds ok?
>
>Be careful how you refer the HV output to ground.....for example if you 
>ground the negative side of the bridge for the positive HV output, and if 
>you should try to ground the negative side of the "not so high voltage" 
>from the center tap,,,if not done properly you will burn up some diodes!
>
>73, Jim, wd4air

Jim is right about this. You can't use a bridge rectifier on either the HV 
tap or the CT, because you'll have conflicting ground references when you 
try to ground the negative side of  either bridge. I believe the only way 
the circuit can work is to use half-wave rectifiers on both the HV and CT 
windings, with one side of the xfmr secondary grounded. A half-wave circuit 
will work because both outputs are referenced to the same ground. I might 
be wrong, but I believe that any other rectifier choice (e.g., full wave, 
bridge, voltage doubler, etc.) will lead to a ground conflict which will 
burn up the transformer and diodes.
73,
Jim Garland W8ZR